You are NOT supposed to try to START the engine with too much fuel in the chamber.
Apparently it doesn't matter where the valves are... rocking the prop back and forth against compression must evaporate the excess methanol or something, because it works no matter how your engine is positioned. Granted, it goes faster on an inverted or side mounted engine.

As for not pulling too much fuel into the engine... how are you going to check that?
The only way I found to start larger four strokes easily is by getting 'em wet... that means too much fuel most of the time. When you get to know your setup you can develop a feeling about the required number of choked prop turns to get the right amount of fuel though.

Starters and four strokes don't mix very well I think, which is why I hand start mine... and trying to start a large four stroke like a .40 two stroke WILL result in sore fingers or nicked props when you use a chicken stick... which is why the "back-flip" works better... and back flipping requires a wet engine... can't have it all...